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EPFO 2015 English Medium Solved Paper
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© examsnet.com
Question : 95
Total: 120
The mean and standard deviation of a set of 16 non- zero positive numbers in an observation are 26 and 3,5 respectively. The mean and standard deviation of another set of 24 non-zero positive numbers without changing the circumstances of both set of observations, are 29 and 3, respectively.
The mean and standard deviation of their combined set of observations will respectively be
27.8 and 3.21
26.2 and 3.32
27.8 and 3.32
26.2 and 3.21
Validate
Solution:
The mean of combined set of observations
=
1
6
×
2
6
+
24
×
29
16
+
24
=
27.8
and standard deviation of combined set of observations
=
√
δ
1
2
×
n
1
+
δ
2
2
×
n
2
n
1
+
n
2
=
√
(
3.5
)
2
×
16
+
(
3
)
2
×
24
16
+
24
=
3209
=
321
© examsnet.com
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